The present invention relates to UCN-1028D derivatives having protein kinase C inhibitory activity and anti-tumor activity and which are useful as anti-tumor agents.
As a substance having perylenequinone skeleton and which is structurally related to the compounds of the present invention, there is known Phleichrome isolated as a plant poison from Cladosporium phlei which causes spots on pasture [Agricultural & Biological Chemistry, 39, 1683 (1975), J. Jap. Pasture, 28 (4), 426 (1983)]. Similar substances UCN-1028A and UCN-1028C having anti-tumor and protein kinase C inhibitory activity are disclosed in European Patent Publication No. 0284358.
The structural formulae of UCN-1028A and UCN-1028C are shown below. ##STR2##